Sliding Grid Puzzle

This is a simple example of XHTML, Javascript, DOM, CSS and PHP working together. View Source to see how it works. Double-click on a square next to the empty one to move a piece. The goal is to get the empty square to the top left and then the pieces should read 1,2,3.. going left-to-right and then top-to-bottom. - Andrew Tomazos, Jan 2007